1. The author first learned
about Suntan in an interview with Col. John D. Seaberg (USAF ret.) at
NASA Hq. on 22 Aug. 1973. Seaberg, a principal in the project, had
learned of my interest in hydrogen from Col. Norman C. Appold (USAF
ret.), who had managed the project. Primary information about Suntan
came from subsequent interviews with other principals, including
Appold, along with some contemporary documentation. The paucity of
the latter was the direct result of deliberate Air Force policy which
not only employed a very high classification category, but resorted
to changes in project numbers and procurements through multiple
channels to disguise the activity. Although the project is now
declassified, the earlier policy makes the tracing of documents
difficult. Particularly elusive was a series of interviews conducted
by an Air Force historian. Dr. Ernest Schweibert, in 1958, but these
were located in 1976.

2. The exact date of
Johnson's visit or visits and whom he saw have not been established.
In an interview by Schweibert on 17 Dec. 1958. Appold placed the time
of the visit between 1 Jan. 1956 and the 18th, when he was summoned
to the Pentagon for a meeting on Johnson's proposal. Johnson most
likely saw Richard E. Horner, who succeeded Trevor Gardner in Feb.
1956 as Sec. of the Air Force for R&D (Gardner had left the
previous November) and Lt. Gen. Donald L. Putt, Chief of Staff for
Development. Both were to be closely involved in Suntan.

6. "Statements by Mr. Robert
Miedel of Directorate of Procurement Hq ARDC, and Mr. Wm. E. Miller
and Lt. Richard Doll of the Sun Tan Procurement Office-December
1958," interviews by Schweibert made available to the author 24 May
1976.

14. According to Ben Rich
in interview, 2 May 1974 (Scott is deceased).

15. Interview with Wesley
A. Kuhrt, United Aircraft Corp., East Hartford, CT, 20 Mar. 1974. The
childhood experience with hydrogen and other biographical information
is also in Robert Zaiman, "The Flexible Mr. Kuhrt," Beehive, Jan. 1960.
Kuhrt became director of research in 1964; in 1975 he was Vice-Pres.
for Technology, United Technology Corp. He holds a number of patents,
among them several for engines using
hydrogen as a fuel.

24. Ibid. According to
James Pierce, a former engineer for Herrick L. Johnston and now
president of Cryovac, Columbus, OH, the liquefier sold to Pratt &
Whitney in 1956 was built in 1952 or 1953 for training purposes for
the Air Force-AEC hydrogen bomb program: interview, 4 June
1974.

31. Pages 10-12 of an
unidentified Pratt & Whitney Aircraft report, shown the author by
William Sens. The data identified the engine serial number, date
fabrication started, date of final assembly, date of first run, date
removed from the test stand, the amount of nitrogen, hydrogen, and
liquid hydrogen consumed, and brief comments on the outcome of the
tests.

52. Nunziato is emphatic
that the cost was on the order of $100 million and Putt, who admits
to not remembering figures very well, concurs (interviews 30 Apr.
1974). Seaberg and William Miller (procurement) also believe the $100
million figure (Seaberg to author, 1 Sept. 1976; telephone interview
with Miller, 1 Sept. 1976).